Table 2.

Characteristics of endoscopic submucosal dissection procedures

	Treatment group	Control group	p-value
	n = 16	n = 16
Size of carcinoma, mm mean ± SD (range)	58 ± 16 (28–92)	53 ± 19 (30–90)	0.40
Size of resected specimen, mm mean ± SD (range)	68 ± 14 (43–97)	62 ± 17 (39–101)	0.29
Depth of invasion, n (m1/m2/m3/sm1/sm2*)	2/11/2/0/1	2/6/6/0/2	0.35
Operation time, min mean ± SD (range)	89.6 ± 37.5 (36–176)	88.3 ± 44.5 (44–235)	0.93
Pathological margin free, n (%)	15 (93.8)	15 (93.8)	0.99
Mucosal defect of circumference, n (<75% / ≥75%)	11/5	11/5	0.99
Perforation by ESD, n (%)	0/16 (0)	0/16 (0)	0.55

Abbreviations: m1, carcinoma in situ; m2, intramucosal invasive carcinoma limited to the lamina propria mucosa; m3, carcinoma limited to the muscularis mucosa; sm2, submucosal invasion between sm1 (slight invasion less than 200 μm in depth) and sm3 (massive invasion); SD, standard deviation; ESD, endoscopic submucosal dissection.

*Three patients with sm2 invasion had relative contraindications for surgical intervention for one or more of the following reasons: age considerations (the patients were 76, 79 and 89 years old), serious medical conditions (cerebral vascular disease, multiple primary cancers, low performance status), and/or patients’ decisions to decline surgery. A treatment plan for these patients was carefully chosen under full informed consent.